Amorphous solid dispersions

ABSTRACT

The disclosure provides new, stable, pharmaceutically acceptable amorphous solid dispersions of 1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one, together with methods of making and using them, and pharmaceutical compositions comprising them.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a United States application under 35 U.S.C. § 371 claiming priority to and the benefit of International Application No. PCT/US2017/054962, filed on Oct. 3, 2017, which claims priority to and the benefit of U.S. Provisional Application Ser. No. 62/407,285, filed on Oct. 12, 2016, the contents of each of which are hereby incorporated by reference in their entireties.

FIELD

This disclosure relates to certain novel amorphous solid dispersion formulations of a substituted heterocycle fused gamma-carboline, the manufacture of such dispersions, pharmaceutical compositions comprising such dispersions, and uses thereof, e.g., in the treatment of diseases or abnormal conditions involving or mediated by the 5-HT_(2A) receptor, serotonin transporter (SERT), and/or dopamine D₁/D₂ receptor signaling pathways.

BACKGROUND

1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one (sometimes referred to as 4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8(7H)-yl)-1-(4-fluorophenyl)-1-butanone, or Lumateperone or as ITI-007), has the following structure:

ITI-007 is a potent 5-HT_(2A) receptor ligand (Ki=0.5 nM) with strong affinity for dopamine (DA) D2 receptors (K_(i)=32 nM) and the serotonin transporter (SERT) (K_(i)=62 nM), but negligible binding to receptors associated with cognitive and metabolic side effects of antipsychotic drugs (e.g., H1 histaminergic, 5-HT_(2C), and muscarinic receptors). ITI-007 is currently in clinical trials, i.e., for the treatment of schizophrenia. While ITI-007 is a promising drug, its production and formulation present distinct challenges. In free base form, ITI-007 is an oily, sticky solid, with poor solubility in water. Making salts of the compound has proven to be unusually difficult. A hydrochloride salt form of ITI-007 was disclosed in U.S. Pat. No. 7,183,282, but this salt was hygroscopic and shows poor stability. A toluenesulfonic acid addition salt (tosylate) of ITI-007 was finally identified and described in WO 2009/114181. Both of these publications are incorporated by reference in their entirety.

Nevertheless, there remains a need for alternative stable, pharmaceutically acceptable solid forms of ITI-007 which can be readily incorporated into galenic formulations.

It has been disclosed that for a number of drugs, amorphous forms exhibits different dissolution characteristics, and in some cases different bioavailability patterns, compared to crystalline forms of the same drug. For some therapeutic indications, one bioavailability pattern may be favored over another. For example, an amorphous form of Cefuroxime axetil exhibits higher bioavailability than the crystalline form. Thus, amorphous solid dispersions are a promising alternative to traditional crystalline active pharmaceutical ingredients.

Pure amorphous drug forms tend to be unstable. As amorphous forms are thermodynamically unstable relative to the corresponding crystal forms, it is well known that amorphous forms would revert back to the stable crystalline form. This usually occurs during storage under various humidity and temperature conditions. Therefore, in order to utilize the amorphous form of a drug, it is necessary to stabilize it to inhibit crystallization of the drug active during the period of product storage.

Discovering suitable excipients that will stabilize the amorphous form of a pharmaceutical drug is a challenge, as some excipients will chemically react with the drug or promote its decomposition, while other excipients will form uniform solid dispersions that are not physically stable, not chemically stable or both.

SUMMARY

Given the difficulties involved in making salts of ITI-007, it was decided to explore whether the compound could be formulated as a physically and chemically stable amorphous solid dispersion. An extensive screen of excipients was undertaken, using various combinations of agents at different ratios and using different production methods. Dispersions were evaluated based on physical appearance and texture, X-ray powder diffraction (XRPD), modulated differential scanning calorimetry (mDSC), thermogravimetric analysis (TGA), and high-performance liquid chromatography (HPLC). Sixteen potential excipients were screened under a total of forty-four conditions, and three pharmaceutically acceptable amorphous solid dispersions were discovered.

The present disclosure provides three amorphous solid dispersions of ITI-007 free base comprising (1) ITI-007 free base at a 5:95 to 50:50 weight ratio to cellulose acetate excipient; (2) ITI-007 free base at a 25:75 to 75:25 weight ratio to cellulose acetate phthalate excipient; and (3) ITI-007 free base at a 25:75 to 75:25 weight ratio to hydroxypropylmethyl cellulose phthalate excipient.

The disclosure thus provides novel amorphous solid dispersion forms of ITI-007 free base, which dispersions are especially advantageous for use in the preparation of galenic formulations, together with methods of making and using the same.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 depicts an overlay of X-ray powder diffraction patterns for dispersions of ITI-007 free base with cellulose acetate.

FIG. 2 depicts an overlay of X-ray powder diffraction patterns for dispersions of ITI-007 free base with cellulose acetate phthalate.

FIG. 3 depicts an overlay of X-ray powder diffraction patterns for dispersions of ITI-007 free base with hydroxypropylmethyl cellulose phthalate (grade 55) (HPMC-P).

For each of FIGS. 1, 2 and 3, the top pattern is the 25:75 ITI-007 free base/excipient dispersion as-generated; the second pattern is the 25:75 dispersion post-stress; the third pattern is the 50:50 ITI-007 free base/excipient dispersion as-generated; the bottom pattern is the 50:50 dispersion post-stress.

FIG. 4 depicts mDSC and TGA thermograms for a 25:75 dispersion of ITI-007 free base with cellulose acetate.

FIG. 5 depicts mDSC and TGA thermograms for a 50:50 dispersion of ITI-007 free base with cellulose acetate phthalate.

FIG. 6 depicts mDSC and TGA thermograms for a 50:50 dispersion of ITI-007 free base with HPMC-P.

DETAILED DESCRIPTION

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by referenced in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed herein and elsewhere in the specification should be understood to refer to percentages by weight. The amounts given are based on the active weight of the material.

In a first embodiment, the present disclosure provides 1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one (ITI-007) free base in the form of an amorphous solid dispersion comprising cellulose acetate excipient in a ratio of 5:95 to 50:50 ITI-007 free base to cellulose acetate (Dispersion 1). The present disclosure further provides the following Compositions:

-   -   1.1. Dispersion 1, wherein the dispersion comprises ITI-007 free         base and cellulose acetate in a weight ratio of 5:95 up to         50:50, but excluding the ratio 50:50.     -   1.2. Dispersion 1 or 1.1, wherein the dispersion comprises         ITI-007 free base and cellulose acetate in a weight ratio of         5:95 to 49:51, e.g., 5:95 to 45:55, or 10:90 to 40:60, or 15:85         to 35:65, or 20:80 to 30:70, or 22:78 to 28:82, or 23:77 to         27:83, or 24:76 to 26:74, or about 25:75.     -   1.3. Any foregoing dispersion, wherein the dispersion is x-ray         amorphous, e.g., as shown by XRPD analysis.     -   1.4. Any foregoing dispersion, wherein the X-ray diffraction         pattern is free of peaks characteristic of the excipient.     -   1.5. Any foregoing dispersion, wherein the dispersion shows a         single glass transition temperature (T_(g)) above 75° C., e.g.,         at a temperature above 100° C., or at a temperature above 150°         C., e.g., as shown by mDSC analysis.     -   1.6. Dispersion 1.5, wherein the dispersion shows a single glass         transition temperature above 160° C., or between 165° C. and         170° C., or at about 167° C.     -   1.7. Any foregoing dispersion, wherein the dispersion shows a         change in heat capacity (ΔCp) of 0.1 to 0.5 J/g-° C., e.g., from         0.2 to 0.3 J/g-° C., or about 0.2 J/g-° C., e.g., as shown by         mDSC.     -   1.8. Any foregoing dispersion, wherein the dispersion shows less         than 10% weight loss up to a temperature of 100° C., e.g., as         shown by TGA analysis.     -   1.9. Dispersion 1.8, wherein the dispersion shows less than 8%         weight loss up to a temperature of 100° C., e.g., less than 7%         weight loss, or less than 6% weight loss, or less than 5% weight         loss, or less than 4% weight loss, or less than 3% weight loss,         up to a temperature of 100° C.     -   1.10. Any foregoing dispersion, wherein the dispersion shows no         changes in appearance or texture after 7 days at 75% relative         humidity at 40° C.     -   1.11. Any foregoing dispersion, wherein the dispersion shows         greater than 90% chemical stability of ITI-007 after 7 days at         75% relative humidity at 40° C., e.g., as judged by HPLC.     -   1.12. Dispersion 1.11, wherein the dispersion shows greater than         95%, or greater than 96%, or greater than 97% or greater than         98%, or greater than 99% chemical stability of ITI-007 after 7         days at 75% relative humidity at 40° C.     -   1.13. Any foregoing dispersion, wherein the dispersion is         manufactured by a method comprising dissolving ITI-007 free base         and the selected excipient in a suitable solvent or mixture of         solvents and removing the solvent, e.g., by lyophilizing the         solution, to obtain the amorphous solid dispersion.     -   1.14. Dispersion 1.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol, ethanol,         tetrahydrofuran, acetone, and mixtures thereof.     -   1.15. Dispersion 1.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol or a         dioxane/methanol mixture, e.g., a 90:10 to 98:2 ratio of dioxane         to methanol, or a 92:8 to 95:5 ratio, or about a 93:7 ratio of         dioxane to methanol.     -   1.16. Any foregoing dispersion, wherein the dispersion exhibits         any combination of characteristics as described in 1.1-1.15.

In a second embodiment, the present disclosure provides ITI-007 free base in the form of an amorphous solid dispersion comprising cellulose acetate phthalate excipient in a ratio of 25:75 to 75:25 ITI-007 free base to cellulose acetate phthalate (Dispersion 2). The present disclosure further provides the following Compositions:

-   -   2.1. Dispersion 2, wherein the dispersion comprises ITI-007 free         base and cellulose acetate phthalate in a weight ratio of from         25:75 up to 75:25, but excluding the ratios 25:75 and 75:25.     -   2.2. Dispersion 2 or 2.1, wherein the dispersion comprises         ITI-007 free base and cellulose acetate phthalate in a weight         ratio of 26:74 to 74:26, e.g., 30:70 to 70:30, or 35:65 to         65:35, or 40:60 to 60:40, or 42:58 to 58:42, or 44:56 to 56:44,         or 45:55 to 55:45, or 47:53 to 53:47, or 48:52 to 52:48, or         49:51 to 51:49, or about 50:50.     -   2.3. Any foregoing dispersion, wherein the dispersion is x-ray         amorphous, e.g., as shown by XRPD analysis.     -   2.4. Any foregoing dispersion, wherein the X-ray diffraction         pattern is free of peaks characteristic of the excipient.     -   2.5. Any foregoing dispersion, wherein the dispersion shows a         single glass transition temperature (T_(g)) above 75° C., e.g.,         at a temperature above 85° C., or at a temperature above 95° C.,         e.g., as shown by mDSC analysis.     -   2.6. Dispersion 2.5, wherein the dispersion shows a single glass         transition temperature above 100° C., or between 105° C. and         115° C., or at about 107° C.     -   2.7. Any foregoing dispersion, wherein the dispersion shows a         change in heat capacity (ΔCp) of 0.1 to 0.6 J/g-° C., e.g., from         0.2 to 0.5 J/g-° C., or about 0.4 J/g-° C., e.g., as shown by         mDSC.     -   2.8. Any foregoing dispersion, wherein the dispersion shows less         than 10% weight loss up to a temperature of 100° C., e.g., as         shown by TGA analysis.     -   2.9. Dispersion 2.8, wherein the dispersion shows less than 8%         weight loss up to a temperature of 100° C., e.g., less than 7%         weight loss, or less than 6% weight loss, or less than 5% weight         loss, or less than 4% weight loss, or less than 3% weight loss,         up to a temperature of 100° C.     -   2.10. Any foregoing dispersion, wherein the dispersion shows no         changes in appearance or texture after 7 days at 75% relative         humidity at 40° C.     -   2.11. Any foregoing dispersion, wherein the dispersion shows         greater than 90% chemical stability of ITI-007 after 7 days at         75% relative humidity at 40° C., e.g., as judged by HPLC.     -   2.12. Dispersion 2.11, wherein the dispersion shows greater than         95%, or greater than 96%, or greater than 97% or greater than         98%, or greater than 99% chemical stability of ITI-007 after 7         days at 75% relative humidity at 40° C.     -   2.13. Any foregoing dispersion, wherein the dispersion is         manufactured by a method comprising dissolving ITI-007 free base         and the selected excipient in a suitable solvent or mixture of         solvents and removing the solvent, e.g., by lyophilizing the         solution, to obtain the amorphous solid dispersion.     -   2.14. Dispersion 2.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol, ethanol,         tetrahydrofuran, acetone, and mixtures thereof.     -   2.15. Dispersion 2.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol or a         dioxane/methanol mixture, e.g., a 90:10 to 98:2 ratio of dioxane         to methanol, or a 92:8 to 95:5 ratio, or about a 93:7 ratio of         dioxane to methanol.     -   2.16. Any foregoing dispersion, wherein the dispersion exhibits         any combination of characteristics as described in 2.1-2.15.

In a third embodiment, the present disclosure provides ITI-007 free base in the form of an amorphous solid dispersion comprising hydroxypropylmethyl cellulose phthalate (HPMC-P) excipient in a ratio of 25:75 to 75:25 ITI-007 free base to HPMC-P (Dispersion 3). The present disclosure further provides the following Compositions:

-   -   3.1. Dispersion 3, wherein the dispersion comprises ITI-007 free         base and HPMC-P in a weight ratio of from 25:75 up to 75:25, but         excluding the ratios 25:75 and 75:25.     -   3.2. Dispersion 3 or 3.1, wherein the dispersion comprises         ITI-007 free base and HPMC-P in a weight ratio of 26:74 to         74:26, e.g., 30:70 to 70:30, or 35:65 to 65:35, or 40:60 to         60:40, or 42:58 to 58:42, or 44:56 to 56:44, or 45:55 to 55:45,         or 47:53 to 53:47, or 48:52 to 52:48, or 49:51 to 51:49, or         about 50:50.     -   3.3. Any foregoing dispersion, wherein the dispersion is x-ray         amorphous, e.g., as shown by XRPD analysis.     -   3.4. Any foregoing dispersion, wherein the X-ray diffraction         pattern is free of peaks characteristic of the excipient.     -   3.5. Any foregoing dispersion, wherein the dispersion shows a         single glass transition temperature (T_(g)) above 75° C., e.g.,         at a temperature above 80° C., or at a temperature above 85° C.,         e.g., as shown by mDSC analysis.     -   3.6. Dispersion 3.5, wherein the dispersion shows a single glass         transition temperature above 90° C., or between 92° C. and 98°         C., or at about 95° C.     -   3.7. Any foregoing dispersion, wherein the dispersion shows a         change in heat capacity (ΔCp) of 0.1 to 0.5 J/g-° C., e.g., from         0.2 to 0.4 J/g-° C., or about 0.3 J/g-° C., e.g., as shown by         mDSC.     -   3.8. Any foregoing dispersion, wherein the dispersion shows less         than 10% weight loss up to a temperature of 100° C., e.g., as         shown by TGA analysis.     -   3.9. Dispersion 3.8, wherein the dispersion shows less than 8%         weight loss up to a temperature of 100° C., e.g., less than 7%         weight loss, or less than 6% weight loss, or less than 5% weight         loss, or less than 4% weight loss, or less than 3% weight loss,         up to a temperature of 100° C.     -   3.10. Any foregoing dispersion, wherein the dispersion shows no         changes in appearance or texture after 7 days at 75% relative         humidity at 40° C.     -   3.11. Any foregoing dispersion, wherein the dispersion shows         greater than 90% chemical stability of ITI-007 after 7 days at         75% relative humidity at 40° C., e.g., as judged by HPLC.     -   3.12. Dispersion 3.11, wherein the dispersion shows greater than         95%, or greater than 96%, or greater than 97% or greater than         98%, or greater than 99% chemical stability of ITI-007 after 7         days at 75% relative humidity at 40° C.     -   3.13. Any foregoing dispersion, wherein the dispersion is         manufactured by a method comprising dissolving ITI-007 free base         and the selected excipient in a suitable solvent or mixture of         solvents and removing the solvent, e.g., by lyophilizing the         solution, to obtain the amorphous solid dispersion.     -   3.14. Dispersion 3.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol, ethanol,         tetrahydrofuran, acetone, and mixtures thereof.     -   3.15. Dispersion 3.13, wherein the solvent or mixture of         solvents is selected from dioxane, methanol or a         dioxane/methanol mixture, e.g., a 90:10 to 98:2 ratio of dioxane         to methanol, or a 92:8 to 95:5 ratio, or about a 93:7 ratio of         dioxane to methanol.     -   3.16. Any foregoing dispersion, wherein the dispersion exhibits         any combination of characteristics as described in 3.1-3.15.

In a second aspect, the present disclosure provides a process (Process 1) for the production of Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq., comprising the steps of:

-   -   (a) combining         1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one         (ITI-007) free base with the selected excipient in a suitable         solvent or mixture of solvents, e.g., selected from dioxane,         methanol, ethanol, tetrahydrofuran, acetone, and mixtures         thereof; and     -   (b) removing the solvent and recovering the amorphous solid         dispersion thus formed, e.g., by lyophilization of the solution.

In another embodiment of the second aspect, the solvent or mixture of solvents for Process 1 is selected from dioxane, methanol or a dioxane/methanol mixture, e.g., a 90:10 to 98:2 ratio of dioxane to methanol, or a 92:8 to 95:5 ratio, or about a 93:7 ratio of dioxane to methanol, optionally wherein the solvent is removed by lyophilization.

Solid dispersion, as used herein, refers to the dispersion of an active pharmaceutical ingredient, i.e., ITI-007, in an inert excipient or matrix (carrier), where the active ingredient could exist in a finely crystalline, solubilized or amorphous state. The excipient in a solid dispersion is typically a polymer. The most important role of the polymer in a solid dispersion is to reduce the molecular mobility of the pharmaceutical active to avoid phase separation and re-crystallization of the active during storage. The amorphous form of the active is associated with a higher energy state as compared to its crystalline counterpart, and therefore, significantly less external energy is required to effect dissolution (e.g., in the gastrointestinal tract or elsewhere in the body).

In a third aspect, the present disclosure provides a pharmaceutical composition (Composition 1) comprising Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq., in combination or association with a pharmaceutically acceptable diluent or carrier. In some embodiments, the pharmaceutical composition is in the form of a tablet or capsule for oral administration. In some embodiments, the pharmaceutical composition is in the form of a depot formulation for use as a long-acting injectable (LAI). The pharmaceutical composition may further comprise any suitable pharmaceutically acceptable excipient, such as: diluents such as starches, pregelatinized starches, lactose, powdered celluloses, microcrystalline celluloses, dicalcium phosphate, tricalcium phosphate, mannitol, sorbitol, xylitol, sugar and the like; binders such as acacia, guar gum, tragacanth, gelatin, polyvinylpyrrolidones such as polyvinylpyrrolidones (PVP K-30,K-90), poly (vinyl pyrrolidone-co-vinyl acetate) (PVP-VA) and the like, hydroxypropyl celluloses, hydroxypropyl methylcellulose, cellulose acetate, hydroxypropyl methylcellulose acetate succinate (HPMC-AS) and the like; disintegrants such as starches, sodium starch glycolate, pregelatinized starches, crospovidones, croscarmellose sodium and the like; lubricants such as stearic acid, magnesium stearate, zinc stearate and the like; glidants such as colloidal silicon dioxide and the like; solubility or wetting enhancers such as anionic or cationic or neutral surfactants; maltodextrin, complex forming agents such as various grades of cyclodextrins and resins; release rate controlling agents such as hydroxypropyl celluloses, hydroxymethyl celluloses, hydroxypropyl methylcelluloses, ethylcelluloses, methylcelluloses, various grades of methyl methacrylates, waxes and the like; and film formers, plasticizers, colorants, flavoring agents, sweeteners, viscosity enhancers, preservatives, antioxidants, and the like.

In another embodiment of the third aspect, the composition may further comprise one or more anti-oxidants, for example, tocopherol, butylated hydroxytoluene (BHT), propyl gallate (OPG), or and ascorbic acid, or the like. The inclusion of an anti-oxidant may further improve the chemical stability of the dispersions by preventing oxidative chemical degradation of the ITI-007 active. In another embodiment, the dispersion itself is formulated to include such an anti-oxidant.

In another aspect, the present disclosure provides Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq., or a pharmaceutical composition comprising Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq., e.g., Composition 1, for use in treating a disease or abnormal condition involving or mediated by the 5-HT_(2A) receptor, serotonin transporter (SERT), and/or dopamine D₁/D₂ receptor signaling pathways, e.g., a disorder selected from obesity, anorexia, bulimia, depression, anxiety, psychosis, schizophrenia, migraine, obsessive-compulsive disorder, sexual disorders, depression, schizophrenia, migraine, attention deficit disorder, attention deficit hyperactivity disorder, obsessive-compulsive disorder, sleep disorders, conditions associated with cephalic pain, social phobias, or dementia.

In another embodiment, the invention provides a method for the prophylaxis or treatment of a human suffering from a disease or abnormal condition involving or mediated by the 5-HT_(2A) receptor, serotonin transporter (SERT), and/or dopamine D₁/D₂ receptor signaling pathways, e.g., a disorder selected from obesity, anorexia, bulimia, depression, anxiety, psychosis, schizophrenia, migraine, obsessive-compulsive disorder, sexual disorders, depression, schizophrenia, migraine, attention deficit disorder, attention deficit hyperactivity disorder, obsessive-compulsive disorder, sleep disorders, conditions associated with cephalic pain, social phobias, or dementia, comprising administering to a patient in need thereof a therapeutically effective amount of Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq., or a pharmaceutical composition comprising Dispersion 1, et seq., or Dispersion 2, et seq., or Dispersion 3, et seq, e.g., Composition 1.

EXAMPLES

The following equipment and methods are used to isolate and characterize the exemplified co-crystal forms:

X-ray powder diffraction (XRPD): The X-ray powder diffraction studies are performed using a PANalytical X'Pert PRO MPD diffractometer using an incident beam of Cu radiation produced using an Optix long, fine-focus source. An elliptically graded multilayer mirror is used to focus Cu Ku X-ray radiation through the specimen and onto the detector. Prior to analysis, a silicon specimen is analyzed to verify the observed position of the Si (111) peak (consistent with the NIST-certified position, NIST SM 640e). A specimen of the sample is sandwiched between 3-micron thick films and analyzed in transmission geometry. A beam-stop, short antiscatter extension, and antiscatter knife edge is used to minimize the background generated by the air. Soller slits for the incident and diffracted beams are used to minimize broadening from axial divergence. Diffraction patterns are collected using a scanning position-sensitive detector (X'Celerator) located 240 mm from the specimen. Data Collector software v. 2.2b is used for analysis.

Thermogravimetry (TGA) analysis: TGA is performed using a TA Instruments Q5000 or Discovery thermogravimetric analyzer. The sample is placed in an aluminum sample pan and is inserted into the TG furnace. Samples are heated from ambient temperature to 250° C. at a rate of 10° C./minute. Nickel and Alumel are used as the calibration standards.

Modulated Differential Scanning Calorimetry (mDSC): mDSC data is obtained on a TA Instruments Q2000 or 2920 differential scanning calorimeter equipped with a refrigerated cooling system. Temperature calibration is performed using NIST traceable indium metal. The sample is placed into an aluminum T-zero DSC pan, covered with a lid, and the weight is accurately recorded. A weighed aluminum pan configured as the sample pan is placed on the reference side of the cell. Typically, the start temperature is −50° C. and the end temperature is 250° C., with a modulation amplitude of ±1° C. and a 50 second period with an underlying heating rate of 2° C. per minute.

High performance liquid chromatography (HPLC): The high-performance liquid chromatography analyses are performed using an Agilent 1100 series liquid chromatograph equipped with a diode array detector, degasser, quaternary pump, and an auto sampler. The column is a 4.6×100 mm CSH C18 column with 2.5-micron packing (XSelect) running with a 0.1% TFA in water mobile phase A and a 0.1% TFA in acetonitrile mobile phase B, at a flow rate of 0.500 mL/minute. The gradient runs from 95% A to 73% over the first 22 minutes, followed by 6 minutes at 73% A, and followed by 73% A to 30% A over the next 22 minutes. The column temperature is set to 15.0° C., and the detector wavelength is 254 nm with a bandwidth of 100 nm and a reference wavelength of 360 nm. The injection volume is 2.0 microliters.

Example 1: Preparation of Dispersions

Solubility of ITI-007 free base and various excipients is first evaluated in various solvents. It is found that ITI-007 free base shows good solubility (>50 mg/mL) in acetone, ethanol, methanol, dioxane, and 2,2,2-trifluoroethanol (TFE), but relatively poor solubility (5-50 mg/mL) in tert-butanol/water mixtures. However, it is found that solutions of ITI-007 free base in TFE rapidly discolor due to decomposition of the active.

The excipients evaluated are Eudragit L100, polyvinyl acetate, polyvinylpyrrolidone-vinyl acetate copolymer, polyvinylpyrrolidone K-90, polyvinylpyrrolidone S-630, cellulose acetate, cellulose acetate phthalate, Gelucire 50/13, glyceryl monostearate, hydroxypropyl cellulose, hydroxypropyl methyl cellulose phthalate (HPMC-P), hydroxypropyl methyl acetate succinate (HPMC-AS), polyethylene glycol (PEG), PEG-100 succinate, Pluronic F-127, and Soluplus. Excipients were evaluated at one or more of the ratios 25:75, 50:50 and 75:25 ITI-007 free base to excipient.

Based on the solubility analyses, solutions of various excipients with ITI-007 free base are prepared in 3:1 acetone-ethanol. Rotary evaporation is attempted to remove the solvent, but this results in oily materials, instead of solids, in all cases.

Solid dispersions are successfully prepared by lyophilization from solutions of ITI-007 free base and excipient in either dioxane or dioxane-methanol (90:10, 91:9, 92:8, 93:7 or 94:6). Solutions are initially frozen in a dry ice/acetone bath, and then placed in a freeze dryer with the shelf pre-cooled to −75° C. Samples are dried overnight at −50° C., followed by −20° C., then 0° C. over a period of two days. Samples are then secondary dried at 20° C. for four hours, purged with nitrogen then stored in a freezer over desiccant until testing.

Example 2: Preliminary Screen

Solid dispersions obtained from Example 1 are first evaluated by XRPD to determine if they are amorphous. All lyophilization samples using amorphous excipients are found to be x-ray amorphous by XRPD. Lyophilization samples using crystalline excipients (Gelucire 50/13, PEG, PEG-1000 succinate, Pluronic F-127) are found to be disordered with peaks present corresponding only to the excipient. Further observations of the appearance of the solids are shown in Table 1 below. The 50:50 ITI-007/PEG-1000 succinate dispersion is found to be very sticky and is not further evaluated.

Example 3: Stability Evaluation

Solid dispersions from Example 1 are placed into uncapped clear glass vials and the vials are placed into a container maintained for seven days at 75% relative humidity and a temperature of 40° C. As a control, a sample of ITI-007 free base is analyzed in parallel. Samples were observed visually as well as by polarized light microscopy (0.8-10× magnification with crossed polarizers and a first order red compensator). Observations are shown in Table 1. The majority of samples display changes in appearance or texture, indicating the formation of physically unstable amorphous dispersions. For example, some show visible crystallization while others become sticky solids or oils.

Dispersions which are physically stable free-flowing solids are further analyzed by XRPD to confirm that they remain x-ray amorphous or disordered with excipient peaks only. The XRPD results confirm that the visually stable samples remain X-ray amorphous dispersions.

mDSC and TGA analysis is conducted on the physically stable free-flowing samples. A single glass transition temperature in mDSC supports the conclusion that the solid is a non-crystalline miscible dispersion. The two PEG dispersions show an unacceptable low-temperature glass transition at 9 or 10° C., while the glyceryl monostearate dispersion shows no glass transition. The 50:50 cellulose acetate dispersion shows two glass transition temperatures, which suggests a phase-separated material, which is unacceptable. Only the 25:75 cellulose acetate, 25:75 cellulose acetate phthalate, 50:50 cellulose acetate phthalate, 25:75 HPMC-AS, 50:50 HPMC-AS, 25:75 HPMC-P and 50:50 HPMC-P dispersions show acceptable single glass transition temperatures above 75° C.

All samples submitted to mDSC and TGA are then submitted to HPLC analysis to determine the chemical stability of the ITI-007 active agent during the seven-day study. As a control, the ITI-007 free base sample is also analyzed by HPLC. All results are normalized to the ITI-007 content shown by HPLC prior to the seven-day study. A loss of less than 5% ITI-007 by HPLC is considered satisfactory.

Both HPMC-AS dispersions, as well as the 25:75 HPMC-P dispersion show very high material losses by HPLC. The 25:75 cellulose acetate phthalate dispersion shows a low but unacceptable loss of material. Only seven dispersions produce satisfactory results: 25:75 cellulose acetate, 50:50 cellulose acetate, 50:50 cellulose acetate phthalate, 50:50 HPMC-P, 25:75 PEG, 50:50 PEG and 25:75 glyceryl stearate. These dispersions are thus chemically stable.

The combined tests results are shown in Table 1 below.

X-ray Stable for ITI-007/ Amor- 7 days at % ITI-007 Excipient phous 40° C./ T_(g) > change Excipient Ratio Solids? 75% RH 75° C. by HPLC Cellulose 25:75 Yes Yes Yes    0% Acetate (167° C.) 50:50 Yes Yes No  −4.43% 75:25 Yes No Cellulose 25:75 Yes Yes Yes  −5.65% Acetate (142° C.) Phthalate 50:50 Yes Yes Yes  −2.42% (107° C.) 75:25 Yes No Gelucire 25:75 No No 50/13 50:50 No No Glyceryl 25:75 No No No    0% Monostearate 50:50 No No HPC 25:75 Yes No 50:50 Yes No HPMC-AS 25:75 Yes Yes −55.29% MG (88° C.) 50:50 Yes Yes  −8.76% (77° C.) 75:25 Yes No HPMC-P 25:75 Yes Yes −18.89% (123° C.) 50:50 Yes Yes  −0.01% (95° C.) 75:25 Yes No PEG 25:75 No No No  −0.30% 50:50 No No No    0% 75:25 No No PEG-1000 25:75 No No Succinate 50:50 No Pluronic F- 25:75 No No 127 50:50 No No PVAc 25:75 Yes No 50:50 Yes No PVP S-630 25:75 Yes No 50:50 Yes No 75:25 Yes No PVP K-90 25:75 Yes No 50:50 Yes No 75:25 Yes No PVP co-VA 25:75 Yes No 50:50 Yes No 75:25 Yes No Soluplus 25:75 Yes No 50:50 Yes No 75:25 Yes No ITI-007 only 100:0 No No  −5.97%

Of the tested dispersions, it is found that only three are both chemically stable and physically stable: 25:75 cellulose acetate, 50:50 cellulose acetate phthalate, and 50:50 HPMC-P.

It is noted that similar experiments conducted using ITI-007 tosylate salt, instead of ITI-007 free base, result in no stable amorphous dispersions. While most of the ITI-007 tosylate dispersions pass the initial screen (X-ray amorphous or showing only X-ray peaks due to the excipient), all of the resulting initial dispersions display strong physical instability (color and appearance changes, including crystallization of the active agent out of the dispersion) or chemical instability (10-68% decomposition by HPLC). For example, the 25:75 dispersion of ITI-007 tosylate with cellulose acetate produced crystallization of ITI-007 during the aging study; the 50:50 dispersion of ITI-007 tosylate with cellulose acetate phthalate showed about a 52% decrease in ITI-007 content by HPLC; and the 50:50 dispersion of ITI-007 tosylate with HPMC-P showed about a 68% decrease in ITI-007 content by HPLC. These results are unexpected because ITI-007 tosylate is chemically more stable than ITI-007 free base. Thus, it is particularly unexpected that three specific amorphous solid dispersions of ITI-007 free base are physically and chemically stable whereas the corresponding dispersions of ITI-007 tosylate are not. 

What is claimed:
 1. 1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one (ITI-007) free base in the form of an amorphous solid dispersion comprising: (a) cellulose acetate excipient in a ratio of 5:95 to 50:50 ITI-007 free base to cellulose acetate; or (b) cellulose acetate phthalate excipient in a ratio of 25:75 to 75:25 ITI-007 free base to cellulose acetate phthalate; or (c) hydroxypropyl methyl cellulose phthalate (HPMC-P) excipient in a ratio of 25:75 to 75:25 ITI-007 free base to HPMC-P; wherein the X-ray diffraction pattern of the amorphous solid dispersion is free of peaks characteristic of the excipient.
 2. The dispersion of claim 1, wherein the dispersion comprises cellulose acetate excipient in a ratio of 5:95 to 50:50 ITI-007 free base to cellulose acetate.
 3. The dispersion of claim 2, wherein the dispersion comprises ITI-007 free base and cellulose acetate in a weight ratio of 5:95 up to 50:50, but excluding the ratio 50:50.
 4. The dispersion of claim 1, wherein the dispersion comprises cellulose acetate phthalate excipient in a ratio of 25:75 to 75:25 ITI-007 free base to cellulose acetate phthalate.
 5. The dispersion of claim 4, wherein the dispersion comprises ITI-007 free base and cellulose acetate phthalate in a weight ratio of from 25:75 up to 75:25, but excluding the ratios 25:75 and 75:25.
 6. The dispersion of claim 1, wherein the dispersion comprises HPMC-P excipient in a ratio of 25:75 to 75:25 ITI-007 free base to HPMC-P.
 7. The dispersion of claim 6, wherein the dispersion comprises ITI-007 free base and HPMC-P in a weight ratio of from 25:75 up to 75:25, but excluding the ratios 25:75 and 75:25.
 8. The dispersion of claim 1, wherein the dispersion is x-ray amorphous.
 9. The dispersion of claim 1, wherein the dispersion shows a single glass transition temperature (T_(g)) above 75° C.
 10. The dispersion of claim 1, wherein the dispersion shows less than 10% weight loss up to a temperature of 100° C.
 11. The dispersion of claim 1, wherein the dispersion shows no changes in appearance or texture after 7 days at 75% relative humidity at 40° C.
 12. The dispersion of claim 1, wherein the dispersion shows greater than 90% chemical stability of ITI-007 after 7 days at 75% relative humidity at 40° C.
 13. The dispersion of claim 1, wherein the dispersion is manufactured by a method comprising dissolving ITI-007 free base and the selected excipient in a suitable solvent or mixture of solvents and removing the solvent to obtain the amorphous solid dispersion.
 14. The dispersion of claim 13, wherein the solvent or mixture of solvents is selected from dioxane, methanol, ethanol, tetrahydrofuran, acetone, and mixtures thereof.
 15. The dispersion of claim 13, wherein the solvent or mixture of solvents is selected from dioxane, methanol or a dioxane/methanol mixture.
 16. The dispersion of claim 15, wherein the solvent or mixture of solvents is dioxane and methanol in a 90:10 to 98:2 ratio of dioxane to methanol, or a 92:8 to 95:5 ratio, or a 93:7 ratio of dioxane to methanol.
 17. A process for the production of the dispersion of claim 1, comprising the steps of: (a) combining 1-(4-fluoro-phenyl)-4-((6bR,10aS)-3-methyl-2,3,6b,9,10,10a-hexahydro-1H,7H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxalin-8-yl)-butan-1-one (ITI-007) free base with the selected excipient in a suitable solvent or mixture of solvents; and (b) removing the solvent and recovering the amorphous solid dispersion thus formed.
 18. A pharmaceutical composition comprising the dispersion of claim 1, in combination or association with a pharmaceutically acceptable diluent or carrier.
 19. The composition of claim 18, wherein the composition is in the form of a tablet or capsule for oral administration.
 20. The composition of claim 18, wherein the composition is in the form of a depot formulation for use as a long-acting injectable (LAI). 